Wind Turbine Blade Shear Web Bonding

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Solution Overview

Problem

Conventional wind turbine blades experience uneven shear stress distribution in the adhesive bond between shear webs and the blade surfaces, leading to stress peaks and increased adhesive material usage, which can be costly and inefficient.

Innovation Solution

The wind turbine blade incorporates a shear web configuration with a greater number of fibre fabric layers separated by cores, allowing for a more even stress distribution and reducing the width of the adhesive bond, thereby minimizing peak stress values and optimizing the use of fibre fabric and adhesive material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the width of the adhesive bond is increased to reduce tension borne by the adhesive, then the bond strength is improved, but the use of adhesive material increases

Engineering Contradiction:
Improvebond strengthVSAvoidadhesive material usage
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The invention changes the structural parameters of the shear web by introducing multiple fibre fabric layers separated by cores, which modifies the stress distribution pattern in the adhesive bond. This allows achieving the same bond strength with a narrower adhesive bond width, thereby reducing adhesive material usage while maintaining structural integrity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The shear web is constructed as a composite structure with multiple fibre fabric layers and cores, creating a more efficient stress transmission path. This composite configuration enables better stress distribution across the adhesive bond, allowing reduction of bond width without compromising strength

Inventive Principle:
Principle #40Composite materials

2Strength

If the width of the adhesive bond is increased to reduce tension borne by the adhesive, then the bond strength is improved, but the device complexity increases

Engineering Contradiction:
Improvebond strengthVSAvoidshear web structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

Rather than increasing bond width, the invention modifies the internal structure of the shear web (number of layers, core placement) to achieve better stress distribution. This approach improves bond strength while keeping the overall device complexity manageable through systematic structural optimization

Inventive Principle:
Principle #35Parameter changes

3Strength

If the shear stress is transmitted through fibre fabric layers, then the structural capacity is improved, but the shear stress distribution in the adhesive becomes uneven

Engineering Contradiction:
Improveshear stress transmission capacityVSAvoidshear stress distribution uniformity
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The shear web is segmented into multiple fibre fabric layers separated by cores. This segmentation divides the stress transmission function across multiple interfaces, creating a more uniform stress distribution pattern in the adhesive bond while maintaining the overall shear stress transmission capacity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cores act as intermediaries between the fibre fabric layers, helping to distribute shear stress more evenly across the adhesive bond. These intermediate elements prevent stress concentration at single interfaces and promote uniform stress distribution throughout the bonding zone

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3165762B1Wind turbine blade
Publication Date: 2023.12.27 NORDEX ENERGY SPAIN SAU
  • EP3165762B1 patent drawingFigure 1a~1b
  • EP3165762B1 patent drawingFigure 2
  • EP3165762B1 patent drawingFigure 3a~3b

AI summary

Wind turbine blade having at least one longitudinal hollow element that defines an aerodynamic outer surface and an inner cavity having an inner surface. The blade also comprises at least one spar (1), disposed in the inner cavity and bonded to the inner surface by at least two bonding surfaces (13) located on bonding surfaces (2) of the spar (1). The spar (1) comprises, on at least one bonding zone (2), at least three fibre fabric layers (3) and at least one central core (4) and at least one lateral core (5) disposed between the at least three fibre fabric layers (3). This makes it possible to increase the resistance to shear stresses in the adhesive bond of the spar (1) to the inner surface of the longitudinal hollow element and decrease the required amount of adhesive.